Muffler for telephone bells



Dec. 6, 1949 KEARNs 2,490,522

MUFFLER FOR TELEPHONE BELLS Filed May 28, 1947 fnveni'or Harry H. K earns 3 I W I. A Z'iorney Patented Dec. 6, 1949 UNITED STATES PATENT OFFICE MUFFLER FOR TELEPHONE BELLS Harry A. Kearns, Uniontown, Pa.

Application May 28, 1947, Serial No. 751,090

2 Claims.

My invention relates to a muffler for electric bells in general, including door bells, and alarm bells of all kinds, but refer more particularly to telephone bells near a sick bed in order to subdue the sound of the bell, so as not to disturb or alarm a patient. The invention may also be useful in warfare for application on trench telephones, where a very faint sound is desired in sending or receiving a signal.

These and other objects of my invention will be understood from the subjoined description with the aid of the attached drawing.

Like references refer to the same details in the various views:

In the drawing:

Figure 1 is a plan view of the muiiler as applied to the signalling or ringing mechanism of a telephone;

Figure 2 is an axial section on a plane along line 2-2 of Figure 1; and

Figure 3 is an end view seen from line 33 of Figure 1, showing the muffler proper.

Numeral l denotes two electric coils mounted in a telephone casing 9 on a bridge piece II with wire connection to the signal line with a push button. The bridge piece I I is mounted to oscillate with a clapper 13 for alternately sounding one of the bells l4, which are mounted symmetrically on either side of the clapper l3 in front of the coils I [1.

At the inner end of the setting screw I6 is carried a clamping bar l8, which is guided on a pair of inwardly directed guide fingers l9, fixed in the bracket plate l5. A compression spring 20 is coiled around the inner end of the screw it between the bracket plate 15 and the clamping bar l8, thus tending to advance said clamping bar for contacting the bells [4 with its ends when the screw is turned in one direction, and then mufliing the sound when a signal is given. This spring also exerts necessary pull on the screw to hold it by friction against turning from the effects of vibration, caused by the bells. For greater effect or for deadening the sound com pletely, the tips of the clamping bar l8 may be covered with a small piece of rubber 2|.

The operation of the muffler is the following:

With the parts installed in a telephone box as described, the knob or head ll of the screw 5 is turned about a quarter turn to the right thereby advancing the clamping bar l8 against both bells Hi, this will dull the ringing of the bells l4, when the clapper l3 keeps on hammering against them.

In case it is desired to deaden the sound more completely, the knob I! is turned further. With the ends of the clamping bar being rubber tipped, the muflling will be most effective.

By turning said knob in opposite direction the mufiling will cease and the bells free to give out their full ring.

It is to be understood that the invention as herein disclosed may be varied from the details described and shown without departure from the spirit of the subjoined claims.

I claim:

1. A muffler for use upon a housed signal unit having a pair of bells within the housing, comprising a plate designed to be secured in such housing adjacent to the bells, a pair of long fixed guide members secured to the plate, a damper bar mounted on the guide members for movement lengthwise of the members relative to the bells, the ends of the bar being positioned for each to be moved into contact with a bell, a screw threaded through the plate and connected with the damper bar to effect the said movement of the bar, and a resilient element encircling the screw and interposed between the bar and the plate for securing the screw against rotation under the effect of vibration.

2. In a telephone bell unit including a housing and a pair of bells therein, means for dampening the bells comprising a bracket plate, means for securing the plate to a wall of the housing adjacent to the bells, the plate carrying a pair of spaced parallel pins, a relatively long damper bar having a pair of apertures through which said pins extend whereby the damper bar is slidable on the pins, said damper bar being positioned so that each of its ends will contact a bell when the damper bar is moved in one direction, the ends of the pins remote from the first bar being disposed between the bells whereby the bells prevent the extension of the damper bar to a point where it will run ofi of the pins, a screw member extending through the said one wall of the housing and threaded in the bracket plate, the screw member being disposed between the guide pins and having its inner end rotatably connected with the damper bar, and a coil spring encircling the screw member and interposed between the plate and bar, and functioning to hold the screw against turning under the effect of vibration created by the bells.

HARRY A. KEARNS.

REFERENCES CITED UNITED STATES PATENTS Name Date Acopian Mar. 25, 1919 Number 

